The present invention relates to a plasma display panel (PDP) and a method for fabricating the same. More particularly, the present invention relates to a plasma display panel where fluorescent layers are formed in a discharge space partitioned by barrier ribs and a method for fabricating the same.
A PDP has been given attention as a display panel (low-profile display device) which exhibits an excellent visibility, and its development has been pursued to a high-definition display and a large screen display to foster its versatility in the field of high-definition display in Japan or the like.
The PDP is broadly classified as an AC-driven type or a DC-driven type, or as a surface discharge type or an opposite discharge type. Currently, an AC-driven surface discharge PDP constitutes the mainstream in industry because of its potential high-definition display, large screen display and convenience of production.
The PDP is a self-luminous display panel which structurally has a discharge space defined by a pair of substrates (typically, glass substrates) spaced a minute distance in an opposing relation with the periphery thereof being sealed.
The PDP includes ribs provided equidistantly for partitioning the discharge space. The ribs prevent interference of discharge and color cross-talk.
For example, a PDP of an AC-driven three-electrode surface discharge type suitable for fluorescent color display includes band-like ribs having a height of about 100 xcexcm to about 200 xcexcm provided parallel to and equidistantly from each other along data electrode (address electrode) lines. A front substrate to be combined with an opposing rear substrate having ribs thereon includes display electrode pairs (sustain electrode pairs) for generating main discharge. The display electrode pairs are arranged parallel to each other in a direction crossing the ribs.
Fluorescent layers are formed in elongated grooves between the ribs to convert light by discharge across the display electrode pairs into visible light, thereby achieving display. Therefore, display luminance of the PDP is dependent on strength of discharge, density of fluorescent substances in the fluorescent layers, surface areas of the fluorescent layers, types of the fluorescent substances, reflectance of the rear surface of the fluorescent layers.
In the PDP thus constructed, separation of pixels (discharge regions) in the direction of the display electrodes is made by the ribs whereas the separation of the pixels (discharge regions) in the direction crossing the display electrodes, i.e., in a longitudinal direction of the ribs, is made by narrowing an inter-electrode spacing for generating discharge (referred to as discharge slits or slits hereinafter) as compared with an inter-electrode spacing for generating no discharge (reverse slits), to limit discharge. Here, there rises a problem that the reverse slits, even if having fluorescent layers formed therein, make no contribution as the display areas.
Further, a typical challenge with the PDP as a self-luminous display device is to improve the luminance, or fundamentally, to improve luminous efficiency of fluorescent substances themselves. This challenge is currently dealt with by, for example, changing the shape and the amount of the fluorescent substances applied and by improving the reflectance of a rear surface material.
Therefore, a plasma display panel has been desired which is simply constructed but has further higher luminance than a conventional one.
The inventors of the present invention have found that the aforementioned challenges will readily be attained by providing wall-like projections in locations where the fluorescent layers are to be provided and forming the fluorescent layers so as to cover the wall-like projections, thereby increasing the area coated with the fluorescent substances and realizing a panel with increased luminance.
Thus, the present invention provides a plasma display panel provided with a pair of substrates disposed opposedly to form a discharge space therebetween, a plurality of band-like barrier ribs arranged in parallel on one of the substrates on a rear or front side to partition the discharge space, and fluorescent layers provided in elongated grooves between the barrier ribs, the plasma display panel being characterized in that wall-like projections which are lower than the barrier ribs and high enough to increase a formation area of the fluorescent layers are provided in the elongated grooves between the barrier ribs and the fluorescent layers are formed in the grooves including the wall-like projections between the barrier ribs.
Also, there is provided a method for fabricating a plasma display panel as described above, comprising: in the formation of the wall-like projections and the barrier ribs on one of the substrates on the rear or front side of the plasma display panel, forming a first photosensitive material layer on a substrate; disposing thereon a photolithographic mask having a pattern of the wall-like projections, followed by exposure; without development, forming a second photosensitive material layer on the first photosensitive material layer; disposing thereon a photolithographic mask having a pattern of the barrier ribs, followed by exposure and development, thereby producing a master having the wall-like projections and the barrier ribs formed on the substrate; and producing a transfer mold using the master, filling a barrier rib material in concaves of the transfer mold and transferring the barrier rib material onto the substrate for the plasma display panel; or producing a pressing mold using the master, pressing a barrier rib material on the substrate for the plasma display panel, thereby forming the wall-like projections and the barrier ribs.